Instrument for aerial navigation



H. E. WIMPERIS.

INSTRUMENT FOR AERIAL NAVlGATlON.

APPLICATION FILED APR'. 15, m9.

1,343,952. Patented June 22, 1920.

3 SHEETS-SHEET I.

H. E. WIMPEHIS.

INSTRUMENT FOR AERIAL NAVIGATION.

APPLICATION FILED APR. 15, I919.

mmxxw H. E WIMPERIS. INSTRUMENT FOR AERIAL NAVIGATION.

APPLICATION FILED APR. 15. I9I9.

Patented June 22, 1920.

3 SHEETS-SHEET 3.

d I JHYRHHHI HHHHHHHHHH JAM/ad (5 ML' 412 Z7 114.

#11:- & i; LIN m II! I HHTIDI IIIIIIIVTHIJ. a fl-rll rnflul k frame.

UNITED STATES PATENT OFFICE.

INSTRUMENT FOR AERIAL NAVIGATION.

Application filed April 15, 1919.

T 0 all whom it may concern: Be it known that I, HARRY EVGERTON 1.n- PERIS, a sub ect of the Kin of Great Britain,

residing at The Cottage, (xoring-on-Thames,

England, have invented a new and useful Improvement in Instruments for Aerial Navigation, of which the following is a specification.

I The object of this invention is to provide an instrument for use on aircraft by means of which the direction and velocity of the wind, the drift for any given course steered, the ground speed and the time occupied in making good a definite distance may be ascertained while the craft is in the air.

My invention is illustrated by theaccompanying drawings, of which Figure 1 is a plan, Fig. 2 a longitudinal vertical section and Fig. 3 an elevation looking from the front toward the rear, while Fig. 4 is a diagram illustrating the method of using the instrument.

1 is a frame secured to which are brackets 2 by which the instrument may be secured in position and clamped by means of screws 3. Rotatably mounted within the frame is a bearing ring 4 graduated in degrees and having compass marks marked upon it. In the bearin ring are inserted screws 5 the heads of w ich are adapted to form handles by which the rin can be turned in the 6 is a lubber mark secured to the frame, the instrument being so mounted on the air craft that the line joining the center of the ring to thelubber mark 6 is parallel to the fore and aft line, the direction of flight being from right to left in Figs. 1

and 2.

Rotatably mounted within the ring 4 is a wind ring 7 having secured to it knobs 8 by which it can be turned and carrying a diametral bar 9 along which can be moved a slider'lO on the upper surface of which is an arrow head 11 and a spot 12. Close above the arrow head is a glass disk 13 mounted in the ring 4 and having engraved upon it circles 14 numbered 1, 2, etc., from that nearest the center outward representing 10, 20, etc., miles of wind per hour.

15 is a forward extension of the frame 1, having engraved upon its upper surface a scale of air speeds. Mounted in this extension is a screw 16 provided with a milled head 17 by which it can be turned and on the screw works a nut 18 so constructed that it cannot rotate and car'r'ymg a vertical pivot Specification of Letters Patent.

Patented June 22, 1920.

Serial No. 290,220.

19 rotatably mounted on which is a drift bar 20 on the upper surface of which are engraved two scales, the one 21 of ground speeds, the other 22 of minutes of time. On each end of the bar 20 is a cross bar 23. ()n the right hand ends of these cross bars are beads 24, 24, between which is stretched a wire 25 in the middle of which is another bead 26, these three beads being all of the same color, say, red, while on the left hand ends of the cross bars are beads 27, 27, between which is stretched a wire 28 on which are threaded other beads 29 of a different color from the beads 24 and 26, say, blue.

Above the front end of the bar 20 is secured a bracket 30 carrying a hinge pin 31 on which is mounted an altitude bar 32 which in use is erect but is capable of being turned down into a horizontal position when not in use, a spring 33 holding it in either position. Upon the bar 32 is mounted a slider 34 provided with a knob 35 by which it can be moved along the bar and which engages a longitudinal groove 36 therein. This slider carries two rear aperture sights 37. 37, through which the beads 24, 26, 27 and 29 may be viewed. The front face of the bar is provided with two scales the one 38 on the right for use at low altitudes and conveniently engraved in red to correspond to the red beads, the other 39 on the left for use at high altitudes and conveniently engraved in blue to correspond to the blue beads.

40 is a segment secured to the nut 18 and graduated in degrees on both sides of zero on the fore and aft line. 5

Referring to Fig. 4, let 0 A represent the air speed 011 some course and let A B represent the line of earth drift. Let 0 a represent the air speed on a second course and a 7) represent the line of earth drift.

Then G, the intersection point of A B,

and a b is the wind point and C O repre-' sents the velocity of the wind. the scale being the same as that used in making 0 A and O a proportional to the air speed.

Obviously C A also represents the ground speed to the same scale when on the first course and if the ground speed can be measured the position of the point C can be determined without the need to fly on a second course.

From what has been said above. it will be seen that the method of using the instrument is as follows:

The altitude bar 32 having been raised to rings 14 and corresponding to the reported wind velocity. The head 17 is then turned until an index 41 at the upper surface of the nut 18 comes opposite the graduation of extension 15 corresponding to the air speed, that is, until the distance of the axis of the pivot 19 from the center of the bearing ring is equivalent, on the scale to which the instrument is constructed, to the air speed of .the craft. \Vhile flying on a steady course the ring 4 is turned by means of screws 5 until the course being steered comes opposite lubher mark 6. The drift bar 20 is then turned until it is parallel to the earth drift which can best be noted by sighting on a dropped flare or on some object passed over a short time before. A line is then drawn with a glass marking pencil on the disk 13 along the edge 42 of the bar 20. If the velocity and direction of the wind are as supposed, this line will pass exactly over the spot 12. It will be noted that for clearness of drawing the drift bar and wind arrow are shown in positions which they would not occupy simultaneously.) Should it fail to do so either the estimated velocity or estimated direction of the wind or both is or are incorrect and the machine should then be flown on some new course preferably not less than 45 from the line of the first. Ring 4 should be turned until the mark 6 reads the new course steered, the drift bar should be again set to the drift and a second line should be drawn on the disk along edge 42. Intersection of this line with that formerly drawn will give the correct position for the spot 12, and the bar 9 and slider 10 can be ad justed.

If it be desired to correct the position without altering course, the slider 34 is set with its upper edge opposite the graduation on one of the scales 38, 39, corresponding to the altitude of the aircraft and by means of a stop watch the number of seconds is noted taken by a suitable object on the earth to pass from the line of sight joining the appropriate back sight 37 to one of the beads to the line joining that sight to the next head. The correct position for the spot 12 will then lie under the graduation corresponding to that number on scale 22. The slider 10 is then moved so that the spot 12 occupies this position. The graduation on scale 21 which lies opposite the spot 12 will give the ground speed while the graduation on segment 40 lying beneath the edge 42 0fthe bar 20 will give the drift angle in degrees and this added to or subtracted from the course steered will give the course made good.

hat I claim is 1. In a navigational instrument for use on aircraft, the combination of a frame, a bearing ring rotatable therein, a disk carried by the ring and capable of having lines ruled upon it and a drift bar rotatable over the disk about an axis parallel to the axis of the ring.

2. In a navigational instrument for use on aircraft, the combination of a frame, a bearing ring rotatable therein, a disk carried by the ring and capable of having lines ruled upon it, a pivot capable of movement toward and away from the axis of the ring, the axis of the pivot being parallel to that axis and a drift bar rotatable over the disk about the axis of the pivot.

3. In a navigational instrument for use on aircraft, the combination of a frame, a

bearing ring rotatable therein, a disk car ried by the ring and capable of having lines ruled upon it, a pivot capable of movement toward and away from the axis of the ring, the axis of the pivot being parallel to that axis, a drift bar rotatable over the disk about the axis of the pivot and means for moving the pivot.

4. In a navigational instrument for use on aircraft, the combination of a frame, a bearing ring rotatable therein, a disk carried by the ring and capable of having lines ruled upon it, a screw journaled in the frame, a nut meshing with the screw, means for preventing rotation of the nut, a pivot carried by the nut, the axis of the pivot being parallel to the axis of the ring, and a drift bar mounted on the pivot and capable of movement over the disk.

5. In a navigational instrument for use on aircraft, the combination of a frame, a bearing ring rotatable therein, a disk carried by the ring and capable of having lines ruled upon it, a pivot capable of movement toward and away from the axis of the ring, the axis of the pivot being parallel to that axis, a drift bar rotatable over the disk about the axis of the pivot, a plurality of foresights carried by the drift bar, an altitude bar parallel to the axis of the ring, a slider capable of movement up and down the altitude bar and a backsight carried by the slider.

' 6. In a navigational instrument for use on aircraft, the combination of a frame, a hearing ring rotatable therein, a disk carried by the ring and capable of having lines ruled upon it, a pivot capable of movement toward and away fromthe axis of the ring, the axis of the pivot being parallel to that axis, a drift bar rotatable over the disk about the axis of the pivot, a plurality of foresights carried by the drift bar, an altitude bar car ried by the pivot, a slider capable of movement up and down the altitudebar and a back-sight carried by the slider.

7. In a navigational instrument for use on aircraft, the combination of a frame, a hearing ring rotatable therein, a disk carried by the frame and capable of having lines ruled upon it, a screw journaled in the frame, a nut meshing with the screw, means for pre venting rotation of the nut, a pivot carried by the nut, the axis of the pivot being parallel to the axis of the ring, a drift bar mounted on the pivot and capable of movement over the disk, a plurality of foresights carried by the drift bar, an altitude bar carried by the nut and parallel to the axis of the ring, a slider capable of movement up and down the altitude bar and a backsight carried by the slider.

8. In a navigational instrument for use on aircraft, the combination of a frame, a bearing ring rotatable therein, a glass disk carried by the ring, a drift bar rotatable over the disk about an axis parallel to the axis of the ring, a wind bar beneath the disk capable of rotation about the axis of the disk and a. wind index capable of sliding move ment along the bar.

9. In a navigational instrument for use on aircraft, the combination of a frame, a bearing ring rotatable therein, a glass disk carried by the ring, a pivot capable of movement toward and away from the axis of the ring, the axis of the pivot being parallel to that axis, means for moving the pivot, a drift bar rotatable over the disk about the axis of the pivot, a wind bar beneath the disk capable of rotation about the axis of the disk and a wind index capable of sliding movement along the wind bar.

10. In a navigational instrument for use on aircraft, the combination of a frame, a bearing ring rotatable therein, a glass disk carried by the ring, a screw journaled in the frame, a nut meshing with the screw, means for preventing rotation of the nut, a pivot carried by the nut, the axis of the pivot being parallel to the axis of the ring, a drift' bar mounted on the )ivot and capable of movement over the disk a wind bar beneath the disk capable of rotation about the axis of the disk and a wind index capable of sliding movement along the wind bar.

11. In a navigational instrument for use on aircraft, the combination of a frame, a bearing ring rotatable therein, a glass disk carried by the ring, a pivot capable of movement toward and away from the axis of the ring, the axis of the pivot being parallel to that axis, a drift bar rotatable over the disk about the axis of the pivot, a plurality of foresights carried by the drift bar, an altitude bar carried by the pivot, a slider capable of movement up and down the altitude bar, a backsight carried by the slider, a wind bar rotatable beneath the disk about the axis of the ring and a wind index capable of sliding movement along the bar.

12. In a navigational instrument for use on aircraft the combination of a frame, a bearing ring rotatable therein, a disk carried by the ring and capable of having lines ruled upon it, a segment graduated in degrees and a drift bar rotatable over the disk and segment about an axis parallel to the axis of the ring.

13. In a navigational instrument for use on aircraft, the combination of a frame, a bearing ring rotatable therein, a glass disk carried by the ring, a pivot capable of movement toward and away from the axis of the ring, the axis of the pivot being par allel to that axis, a segment graduated in degrees fixed to the pivot and a drift bar rotatable around the pivot over the disk and segment.

14:. In a navigational instrument for use on aircraft, the combination of a frame, a bearing ring rotatable therein, a glass disk carried by the ring, a screw journaled in the frame, a nut meshing with the screw, means for preventing rotation of the nut, a pivot carried by the nut, the axis of the pivot being parallel to the axis of the ring, a segment graduated in degrees fast on the nut and a drift bar mounted on the pivot and capable of rotation over the disk and segment.

15. In a navigational instrument for use on aircraft, the combination of a frame, a bearing ring rotatable therein, a glass disk carried by the ring, a segment graduated in degrees, a drift bar rotatable over the disk and segment about an axis parallel to the axis of the ring, a wind bar beneath the disk capable of rotation about the axis of the disk and a wind index capable of sliding movement along the bar.

16. In a navigational instrument for use on aircraft, the combination of a frame, a bearing ring rotatable therein, a glass disk carried by the ring, a screw ournaled in the frame, a nut meshing with the screw, means forpreventing rotation of the nut, a segment graduated in degrees fast on the nut, a pivot carried by the nut, the axis of the pivot being parallel to the axis of the ring, a drift bar mounted on the pivot and capable of rotation over the disk and segment, a wind bar beneath the disk capable of rotation about the axis of the disk and a wind index capable of sliding movement along the wind bar.

17. In a navigational instrument for use on aircraft, the combination of a frame, a bearing ring rotatable therein, a glass disk carried by the ring, a screw journaled in the frame, a nut meshing with the screw, means for preventing rotation of the nut, a segment fast on the nut, a pivot carried by the nut, the axis of the pivot being parallel to the axis of the ring, a drift bar mounted on the pivot and capable of movement over the disk and segment, a plurality of foresights carried by the drift bar, an altitude bar carried by the pivot, a slider capable of movement up and down the altitude bar and a backsight carried by the slider.

18. In a navigational instrument for use on aircraft, the combination of a frame, a bearing ring rotatable therein, a glass disk carried by the ring, a screw journaled in the frame, a nut meshing with the screw, means for preventing rotation of the nut, a segment fast on the nut, a pivot carried by the nut, the axis of the pivot being parallel to the axis of the ring, a drift bar mounted on the pivot and capable of movement over the disk and segment, a plurality of foresights carried by the drift bar, an altitude bar car tried by the pivot, a slider capable of movement up and down the altitude bar, a backsight carried by the slider, a wind bar rotata ble beneath the disk about the axis of the ring and a wind index capable of sliding movement along the bar.

19. In a navigational instrument for use on aircraft, the combination of a frame, a bearing ring rotatable therein, a glass disk carried by the ring, a screw journaled in the frame, a nut meshing with the screw, means for preventing rotation of the nut, a segment graduated in degrees fast on the nut, a pivot carried by the nut, the axis of the pivot being parallel to the axis of the ring, a drift bar mounted on the pivot and capable of movement over the disk and segment, two sets of foresights carried by. the drift bar, an altitude bar carried by the pivot and having two scales engraved upon it, a slider capable of movement up and down the altitude bar, two backsights carried by the slider, a wind bar rotatable beneath the disk about the axis of the ring and a wind index capable of sliding movement along the bar.

In testimony that I claim the foregoing as my invention I have signed my name this 6th day of March, 1919.

HARRY EGERTON WIMPERIS. 

